The invention relates to an electric lamp in accordance with the preamble of patent claim 1.
Such an electric lamp is disclosed, for example, in European Patent EP 0 815 578 B1. This patent describes a motor vehicle headlamp which has a lamp vessel with an incandescent filament arranged therein, supply leads for the incandescent filament and a lamp base, the lamp base having a metal ring for holding the lamp vessel and a plastic part provided with electric terminals.
It is the object of the invention to provide an electric lamp, in particular a motor vehicle auxiliary light lamp such as, for example, a brake light lamp or a direction indicator light lamp, with a simplified base, and to specify a method for producing such a lamp.
According to the invention, this object is achieved by the features of claim 1 and claim 6, respectively. Particularly advantageous embodiments of the invention are described in the dependent claims.
As regards a motor vehicle auxiliary light lamp, no such high demands are placed on the alignment of the luminous elementxe2x80x94incandescent filament or discharge arcxe2x80x94with reference to the reflector as is the case with a motor vehicle headlamp. The base design for an auxiliary light lamp can therefore be correspondingly simplified.
The base of the electric lamp according to the invention has an annular metal part of resilient design for holding the lamp vessel, and a plastic part provided with electric terminals, the lamp vessel forming a plug-and-socket connection with the metal part or/and the metal part forming a plug-and-socket connection with the plastic part. At least one electric terminal is designed as a hollow contact pin in which one end of a supply lead projecting from the lamp vessel and serving to supply energy to the at least one luminous element is arranged and fixed. Owing to the resilient configuration of the metal part, the exertion of pressure on the plug-and-socket connection or the plug-and-socket connections can produce in the metal part a mechanical stress that can be maintained by fixing the supply lead in the hollow contact pin. The entire structure of the base is thus held together in a backlash-free arrangement and clamped seat by the connection of supply lead and hollow contact pin. There is no need for any further components to provide the lamp according to the invention with a base.
In order to hold the lamp vessel, the metal part is advantageously equipped with a plurality of integrally formed guide webs and depth-control stops. The spring action of the metal part can be produced advantageously and simply with the aid of the depth-control stops. The plug-and-socket connection between the metal part and the plastic part is advantageously produced by means of a plurality of lugs which are integrally formed on the metal part and can be plugged into fitting slots or cutouts in the plastic part.
In order to anchor the at least one hollow contact pin securely in the plastic part, the contact pin is preferably of cylindrical design and has a bead that enlarges its outside diameter, and a section widened in the shape of a funnel. The funnel-shaped section also serves additionally as a threading aid for the end of the supply lead arranged in the hollow contact pin.
The method according to the invention for producing an electric lamp comprises the work steps of:
providing a prefabricated lamp vessel having at least one luminous element arranged therein and supply leads projecting from the lamp vessel,
providing a prefabricated, annular metal part of resilient design.
The method is characterized in that
a prefabricated plastic part provided with electric terminals is provided, at least one electric terminal being designed as a hollow contact pin,
a plug-and-socket connection is produced between the lamp vessel and the annular metal part of resilient design or/and between the annular metal part of resilient design and the plastic part such that the free end of a supply lead is threaded in the at least one hollow contact pin, and
pressure is exerted on the plug-and-socket connection or on the plug-and-socket connections such that the metal part is under mechanical stress and during this time the free end of the supply lead is welded or soldered to the at least one hollow contact pin.
This ensures a backlash-free clamped seat of the lamp vessel, metal part and plastic part. The mechanical stress is produced in a simple way and advantageously by means of a plurality of depth-control stops for the lamp vessel that are integrally formed on the metal part. For the purpose of producing the plug-and-socket connection with the plastic part, the metal part advantageously has a plurality of integrally formed lugs that are introduced into fitting depressions in the plastic part. Before the production of the plug-and-socket connection or the plug-and-socket connections, one end of the hollow contact pin is advantageously widened in the shape of a funnel in order to ease the threading of the supply lead into the hollow contact pin and to ensure that the contact pin is securely anchored in the plastic part.